Flask



FIG. 1 is a perspective view of a flask showing our new design;

FIG. 2 is an exploded perspective view thereof;

FIG. 3 is a front elevation thereof;

FIG. 4 is a right side elevation thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a rear elevation thereof;

FIG. 7 is a left side elevation thereof; and,

FIG. 8 is a top plan view thereof.

The broken lines indicate unclaimed portions and form no part of the claimed design. 

CLAIM The ornamental design for a flask, as shown and described. 